Aqueous phase sensing of bismuth ion using fluorescent metal-organic framework

In this work, the fluorescent CAU-1-(OH)2 was successfully exploited as a fluorescent probe for bismuth ion (Bi3+) in aqueous solutions, which is the first MOF-based fluorescent sensor for Bi3+ up to date. The MOF can exhibit bright green fluorescence in H2O for the intramolecular proton transfer process between the ligand and H2O molecule. In addition, the carboxylate and hydroxyl groups in the MOF can strongly coordinate with Bi3+. Accordingly, CAU-1-(OH)2 can selectively detect Bi3+ in water in 24 s. In addition, the limit of detection of this MOF was calculated to be 2.16 μM, superior to those of some traditional methods such as spectrophotometry and flow injection potentiometry.